On Sat, Jan 28, 2012 at 02:33:31PM +0100, Eric Dumazet wrote:> Le samedi 28 janvier 2012 à 20:51 +0800, Wu Fengguang a écrit :> > > Would you please create a filesystem and large file on sda and run the> > tests on the file? There was some performance bug on reading the raw> > /dev/sda device file..> > Hmm... latest kernel has the performance bug right now.> > Really if /dev/sda is slow, we are stuck.

What's the block size? If it's < 4k, performance might be hurt.

blockdev --getbsz /dev/sda

> FYI, I started a bisection.

Thank you! If the bisection would take much human time, it should beeasier to collect some blktrace data on reading /dev/sda for analyzes.